1. Field of the Invention
This invention relates to electrical plugs and sockets, and more particularly to an electrical plug or socket having a replaceable overcurrent-protection device provided with safety latch means.
2. Description of the Prior Art
The structure of an electrical plug or socket, having a replaceable overcurrent-protection device as well as its electric circuit components is designed to have the overcurrent-protection device located in a position intermediate the copper prong members of the plug or the copper contact blades of the socket and an extension electrical conductor or electrical equipment when in use. Power supply is connected to one end of the overcurrent-protection device via the copper prong member or the copper contact blade; with, another end of the overcurrent-protection device being connected to the extension electrical conductor or the electrical equipment to complete an electric circuit. As an overload current or a short circuit occurs, the overcurrent-protection device blows out and the electric circuit is cut off without delay. The electric circuit will resume operation after the fault is rectified and the overcurrent-protection device is replaced with a new one. The functioning of such device is well-known in the art and further detailed explanation will be omitted here for simplification. However, conventional plugs or sockets, usually, cannot meet the safety requirement, and this problem still remains to be solved. Therefore, taking into consideration the safe use of electrical equipment, the damage of electrical equipment caused by an overload, the danger resulted from a short circuit or an electrical shock due to the exposure of a bare conductor in the circuit and the requirement of security of human life and property etc., the fundamental requirement of safety should be the primary consideration when designing and constructing an electrical plug or socket. In addition, from the viewpoint of convenience and utility, it is necessary to provide the plug or socket with an overcurrent-protection, and it is also necessary that the overcurrent-protection device can be replaced after its breakdown due to improper use or any other causes so that the plug or socket can resume its function after the fault is rectified. However, conventional plugs or sockets are not satisfactory from a safety standpoint. There are many disadvantages in conventional plugs and sockets. For example, the opening for fitting and removing the overcurrent-protection device is too large so that misuse may occur frequently with the incidence of great danger of electric shock by accidentally touching the live parts via the opening. The enclosure cover thereof tends to be easiily deformed causing it to fall off so that the bare conductor within the plug or socket will be exposed. The construction is complicated and the manufacturing cost is relatively quite high.